Site Mobile Navigation

Joe Hin Tjio, 82; Research Biologist Counted Chromosomes

Dr. Joe Hin Tjio, the research biologist who produced the first correct count of the chromosomes in human cells, died Nov. 27 in Gaithersburg, Md. He was 82.

Dr. Tjio (pronounced CHEE-oh) accomplished that feat in 1956 as a visiting scientist at the University of Lund, Sweden. His surprise discovery helped pave the way to much work in human biology pertaining to chromosomal abnormalities.

He later joined the staff of the National Institutes of Health, and President John F. Kennedy honored him with an outstanding achievement award in 1962.

The nature and functions of chromosomes, the agents of heredity, had been known when Dr. Tjio correctly counted the number of chromosomes. But observing human chromosomes under the microscope had always been more difficult than observing those of other species, and scientists had long assumed that chromosomes normally numbered 48 in each body cell.

Dr. Tjio used an advanced technique to separate chromosomes of embryonic lung tissue on glass slides and, to his own amazement, saw that the actual figure was 46. ''The number was just an incidental finding,'' he recalled many years later.

He continued his study of chromosomes, looking for clues to some of the most baffling and tragic human diseases.

Joe Hin Tjio was born in 1919 to Chinese parents in Java. His father was a photographer, and the son became an accomplished one, too, as an apprentice in the parental studio.

He went to strict Dutch colonial schools, where he learned French, German and English as well as Dutch. He graduated from the School of Agronomy in Bogor, Indonesia, in 1940, and engaged in breeding potatoes, trying to find a disease-proof hybrid.

An error has occurred. Please try again later.

You are already subscribed to this email.

In World War II, when the Japanese Army occupied what was then the Dutch East Indies, he spent three years in an internment camp. Once released, a Red Cross boat for displaced persons took him to the Netherlands, and he spent several years studying and working there, in Denmark and Spain.

But each summer he was at the Institute of Genetics in Lund, where he studied mammalian tissues. He acquired wide expertise in cytogenetics investigating the behavior of chromosomes and genes in cells as they affect heredity and variation.

After gaining international recognition, he came to the United States and received a Ph.D. in biophysics and cytogenetics at the University of Colorado in 1960.

He became associated with the National Institutes in 1959 and worked at the laboratory of experimental pathology of what was then the National Institute of Arthritis and Metabolic Diseases. His work on chromosomes focused on leukemia and mental retardation.

Named a scientist emeritus in 1992, he kept his laboratory space until 1997, when he moved to a retirement community in Gaithersburg.

Dr. Tjio is survived by his wife of 53 years, Inga, and a son, Yu Hin Tjio of Silver Spring, Md.

We are continually improving the quality of our text archives. Please send feedback, error reports,
and suggestions to archive_feedback@nytimes.com.

A version of this obituary; biography appears in print on December 7, 2001, on Page C00013 of the National edition with the headline: Joe Hin Tjio, 82; Research Biologist Counted Chromosomes. Order Reprints|Today's Paper|Subscribe